The present disclosure relates to a semiconductor structure, and more particularly to a fin field effect transistor including asymmetric raised active regions, and a method of manufacturing the same.
One of the key design choices among fin field effect transistors is whether raised active regions formed by selective epitaxy are to be merged with one another or to remain unmerged. Each choice offers advantages and disadvantages. On one hand, fin field effect transistors including unmerged raised active regions benefit from lower contact resistance and improved direct current (DC) performance due to increased silicide contact areas corresponding to wrapping around of the silicides around the faceted surfaces of the unmerged raised active regions. On the other hand, fin field effect transistors including merged raised active regions benefit from reduced parasitic resistance between a gate electrode and contact via structures due to the reduction in the number of contact via structures. For this reason, it is desirable to have merged raised active regions for some fin field effect transistors, and to have unmerged raised active regions for some other fin field effect transistors.